Ip Blacklist doesn't work the way it should be

For 2 years now we have got the 3CX PBX running and we never had problems, but now we have got this strange thing. Sometimes there is a IP Address stored on the IP blacklist because of too many failed authenticationsand that's ok.

But now we have got some IP addresses that keeps getting stored while it is already on the blacklist. See my printscreen... Does any one knowes why this is and why it's not blocked by the first stored IP address?

Before 1 stored IP address was enough to block this from further attacks.